Micro 20 Exam 2 Study Guide

Phylogeny

Classification of living organisms based on their similarities and differences

Taxonomy

Science of classifying organisms into groups (taxa)

Binomial Nomenclature

Two-part naming system for organisms developed by Carl Linnaeus; names are italicized or underlined

Genus Name

First part of a binomial name; always capitalized; always a noun

Species Name

Second part of a binomial name; always lowercase; usually an adjective

Domain

Highest taxonomic category; three exist: Bacteria, Archaea, Eukaryota

Kingdom

Taxonomic level below Domain

Phylum/Division

Taxonomic level below Kingdom

Class

Taxonomic level below Phylum

Order

Taxonomic level below Class

Family

Taxonomic level below Order

Genus

Taxonomic level below Family

Species

Lowest taxonomic level; members can mate and produce fertile offspring

Kingdom Procaryotae (Monera)

Prokaryotes; no nucleus or membrane-bound organelles; oldest known cells (3.5 billion years ago); unicellular

Kingdom Protista

Eukaryotes; mostly unicellular; no tissue organization; most have flagella

Kingdom Fungi

Eukaryotes; unicellular (yeasts) or multicellular (molds); many are saprotrophs

Kingdom Plantae

Eukaryotes; multicellular; photosynthetic

Kingdom Animalia

Eukaryotes; multicellular; heterotrophs; ingest food through a mouth or oral cavity

Domain Archaea

Unique rRNA; no peptidoglycan cell wall; branched membrane lipids; many are extremophiles; rarely cause human disease

Bergey's Manual of Systematic Bacteriology

Most widely accepted bacterial classification system; groups prokaryotes by nucleic acid sequences, morphology, staining, and biochemical characteristics

Gram-Negative Bacteria

Thin peptidoglycan layer; outer membrane with LPS; stain pink/red

Gram-Positive Bacteria

Thick peptidoglycan layer with teichoic acids; no outer membrane; stain purple

Spirochetes

Gram-negative; helical shape; flexible; move in corkscrew pattern using axial filaments (endoflagella); difficult to stain

Rickettsias

Gram-negative Alphaproteobacteria; obligate intracellular parasites; cannot make ATP; transmitted by insects and ticks

Chlamydias

Gram-negative Alphaproteobacteria; cocci-shaped; obligate intracellular parasites; cannot make ATP; transmitted by contact or airborne routes

Mycobacteria

Gram-positive rods; waxy mycolic acid cell wall instead of peptidoglycan; acid-fast; drug resistant; slow-growing; cause chronic infections

Mycoplasmas

No cell wall; pleomorphic; smallest free-living cells (0.1-0.25 µm); resistant to beta-lactam antibiotics; can pass through bacterial filters

Alphaproteobacteria

Gram-negative; oligotrophs (survive in low-nutrient environments); includes Rickettsias, Chlamydias, and Rhizobium

Betaproteobacteria

Gram-negative; eutrophs (require large amounts of organic nutrients); often live between aerobic and anaerobic areas

Gammaproteobacteria

Gram-negative; most diverse class of Proteobacteria; includes many human pathogens; families include Enterobacteriaceae, Vibrionaceae, Pasterellaceae, Moraxellaceae

Deltaproteobacteria

Gram-negative; includes sulfur-reducing bacteria; genera: Bdellovibrio, Desulfovibrio, Myxobacterium

Epsilonproteobacteria

Gram-negative; smallest class of Proteobacteria; microaerophilic; includes Campylobacter and Helicobacter

Phototrophic Bacteria

Gram-negative; use sunlight to make ATP via photosynthesis; use bacteriochlorophylls and carotenoids as pigments

Cyanobacteria

Gram-negative nonproteobacteria; oxygenic photosynthesis; blue-green color; believed to have produced Earth's atmospheric oxygen 1-2 billion years ago; can form harmful blooms

Nocardia

Gram-positive; filamentous; aerobic; often acid-fast; common in soil

Actinomycetes

Gram-positive; filamentous; resemble molds; common in soil; genus Streptomyces produces hundreds of antibiotics

Deeply Branching Bacteria

Closest relatives of the LUCA; diverged ~3.5 billion years ago; base of the phylogenetic tree

LUCA

Last Universal Common Ancestor; common ancestor of all three domains of life

Treponema pallidum

Gram-negative spirochete; causes syphilis

Borrelia burgdorferi

Gram-negative spirochete; causes Lyme disease; transmitted by ticks; produces bulls-eye lesion

Borrelia recurrens

Gram-negative spirochete; causes relapsing fever

Rickettsia rickettsii

Gram-negative Alphaproteobacteria; causes Rocky Mountain spotted fever; transmitted by ticks

Chlamydia trachomatis

Gram-negative Alphaproteobacteria; causes blindness and nongonococcal urethritis (most common STD in U.S.)

Chlamydia psittaci

Gram-negative Alphaproteobacteria; causes parrot fever

Chlamydia pneumoniae

Gram-negative Alphaproteobacteria; causes mild pneumonia

Neisseria gonorrhea

Gram-negative Betaproteobacteria; diplococci; causes gonorrhea; can cause neonatal blindness

Neisseria meningitidis

Gram-negative Betaproteobacteria; diplococci; causes bacterial meningitis

Bordetella pertussis

Gram-negative Betaproteobacteria; causes whooping cough; "P" in DPT vaccine

Pseudomonas aeruginosa

Gram-negative Gammaproteobacteria; secretes green pigment; causes UTIs, burns, septicemia, and pulmonary infections in cystic fibrosis patients

Legionella pneumophila

Gram-negative Gammaproteobacteria; found in water systems; causes Legionnaires' disease and Pontiac fever

Escherichia coli

Gram-negative Gammaproteobacteria; normal intestinal flora; some strains cause UTIs, traveler's diarrhea, and food-borne disease

Salmonella typhi

Gram-negative Gammaproteobacteria; causes typhoid fever

Salmonella enteritidis

Gram-negative Gammaproteobacteria; causes salmonellosis; second most common bacterial food-borne disease in the U.S.

Shigella sonnei

Gram-negative Gammaproteobacteria; most common Shigella in U.S.; causes shigellosis

Shigella flexneri

Gram-negative Gammaproteobacteria; common Shigella in U.S.; causes shigellosis

Shigella dysenteriae

Gram-negative Gammaproteobacteria; rare in U.S.; can be deadly; causes severe dysentery

Klebsiella pneumoniae

Gram-negative Gammaproteobacteria; antibiotic-resistant strains cause pneumonia and nosocomial infections

Yersinia pestis

Gram-negative Gammaproteobacteria; causes bubonic plague (black death); transmitted by fleas

Vibrio cholerae

Gram-negative Gammaproteobacteria; curved rod; causes cholera (profuse watery diarrhea); fatal in up to 50% of untreated cases

Vibrio parahaemolyticus

Gram-negative Gammaproteobacteria; causes gastroenteritis from eating shellfish

Hemophilus influenzae

Gram-negative Gammaproteobacteria; causes meningitis, ear infections, bronchitis, and pneumonia in children

Gardnerella vaginalis

Gram-negative Gammaproteobacteria; causes bacterial vaginitis

Desulfovibrio orale

Gram-negative Deltaproteobacteria; causes periodontal disease

Acinetobacter baumannii

Gram-negative Gammaproteobacteria; multiple drug resistant; major cause of nosocomial infections; high risk for ICU patients

Campylobacter jejuni

Gram-negative Epsilonproteobacteria; most common bacterial food-borne intestinal disease in the U.S.; linked to undercooked chicken

Campylobacter fetus

Gram-negative Epsilonproteobacteria; causes abortions in domestic animals

Helicobacter pylori

Gram-negative Epsilonproteobacteria; causes most gastric ulcers and stomach cancer; 2005 Nobel Prize in Medicine

Staphylococcus aureus

Gram-positive cocci; grape-like clusters; yellow pigment; causes pimples, sties, toxic shock syndrome, food poisoning, and nosocomial infections; MRSA strains resist methicillin; vancomycin is last defense

Streptococcus pneumoniae

Gram-positive cocci; causes bacterial pneumonia, ear infections, and meningitis

Streptococcus pyogenes

Gram-positive cocci; causes strep throat, scarlet fever, rheumatic fever, impetigo, and necrotizing fasciitis (flesh-eating disease)

Lactobacillus bulgaricus

Gram-positive rod; probiotic; used to make yogurt

Lactobacillus acidophilus

Gram-positive rod; probiotic; lives in intestinal tract, vagina, and mouth

Lactobacillus rhamnosus GG

Gram-positive rod; probiotic; used as a dietary supplement

Bacillus anthracis

Gram-positive endospore-forming rod; causes anthrax; large, nonmotile, facultative anaerobe

Bacillus thuringiensis

Gram-positive endospore-forming rod; kills insects; used as a bioinsecticide

Clostridium tetani

Gram-positive endospore-forming rod; obligate anaerobe; causes tetanus; "T" in DPT vaccine

Clostridium botulinum

Gram-positive endospore-forming rod; obligate anaerobe; causes botulism; source of Botox

Clostridium perfringens

Gram-positive endospore-forming rod; obligate anaerobe; causes gas gangrene and foodborne diarrhea

Clostridium difficile

Gram-positive endospore-forming rod; obligate anaerobe; causes diarrhea especially after antibiotic use

Listeria monocytogenes

Gram-positive nonsporing rod; survives in phagocytic cells and refrigerators; causes listeriosis; dangerous in pregnancy (can cause stillbirth)

Corynebacterium diphtheriae

Gram-positive irregular nonsporing rod; club-shaped; pleomorphic; causes diphtheria; "D" in DPT vaccine

Propionibacterium acnes

Gram-positive irregular nonsporing rod; causes acne

Mycobacterium tuberculosis

Gram-positive (acid-fast) rod; waxy cell wall; slow-growing; causes tuberculosis

Mycobacterium leprae

Gram-positive (acid-fast) rod; waxy cell wall; causes leprosy

Nocardia asteroides

Gram-positive filamentous rod; acid-fast; causes pulmonary infections similar to tuberculosis, mycetoma, and abscesses

Mycoplasma pneumoniae

Wall-less (not Gram-positive or Gram-negative); pleomorphic; causes walking pneumonia; ~2 million infections/year in the U.S.

Halobacterium salinarum

Archaea; halophile; may be oldest organism on Earth (found in 250-million-year-old fossils); uses bacteriorhodopsin for photosynthesis

Deinococcus radiodurans

Deeply branching bacterium; "Conan the Bacterium"; polyextremophile; survives extreme heat, acidity, vacuum, drought, and radiation

Pseudopods

False feet; used by Amebozoa to move and engulf food

Cilia

Short hair-like appendages used for movement or feeding

Flagella

Long whip-like appendages used for movement

Nonmotile (Protozoa)

Some protozoa have no means of movement; example: Apicomplexans

Trophozoite

Active feeding and growing stage of a protozoan

Cyst

Protective-walled dormant stage formed under harsh conditions

Nutritional Adaptations of Protozoa

Most are heterotrophic; some ingest organisms; parasitic forms absorb nutrients from host; digestion in vacuoles

Supergroup Amebozoa

Move via pseudopods; includes species causing amoebic dysentery

Supergroup Chromalveolata

Contains many medically important pathogens; includes Apicomplexans and Ciliates

Apicomplexans

Parasites with an apical complex to penetrate host cells; example: Plasmodium

Ciliates

Covered with cilia; most are not human parasites; example: Balantidium coli

Supergroup Excavata

Primitive eukaryotes with limited metabolism; includes Fornicata, Euglenozoa, and Parabasalids